Nerve injury induced protein 1 (Ninjurin1) was originally described in neuroscience in which the expression of Ninjurin1 was regulated by Schwann cells and dorsal root ganglion neuronal cells of damaged nerve tissues. After the first discovery of Ninjurin1, the widespread expression of Ninjurin1 in adult and embryonic tissues have been observed including bone marrow, peripheral blood lymphocytes, thymus, and heart. Currently, the Ninjurin1 mediated positive regulation of pre-osteoclasts fusion and osteoclast development was reported. The bone homeostasis is dynamically balanced by bone-resorbing activity of osteoclast and bone-forming activity of osteoblast. Until now, the role of Ninjurin1 was never been described in osteoblastogenesis. Therefore, in this study, we have evaluated the expression and function of Ninjurin1 in osteoblast. The ample expression of Ninjurin1 was observed in bone marrow of mouse tibia sections but it was barely expressed in osteocytes. And also the expression levels of Ninjurin1 were gradually increased during osteoblast differentiation of calvarial pre-osteoblast, C2C12, and MC3T3-E1 cells. Importantly, the expression of Ninjurin1 was increased in the absence of osteogenic stimulus, BMP2, which suggests the cell density-dependent regulation of Ninjurin1. The controlled expression of Ninjurin1 by cell-density was evidently shown in not only pre-osteogenic osteoblast lineage cells but also in non-osteogenic cancer cells such as HeLa and A549 cells. In addition, the isoform-specific knockdown of Ninjurin1 remarkably reduced the alkaline phosphatase (ALP)-positive osteoblast differentiation. Thus, our results suggest a previously unappreciated mechanism of Ninjurin1 expression and also suggest its role on osteoblastogenesis.

The Hippo pathway was originally discovered in Drosophila by genetic screening and it has been shown to be conserved in various organisms including human. Until now, the essential roles of Hippo pathway in regulating cell proliferation, apoptosis, tumorigenesis, and organ size control is extensively studied. Currently, Mats1/2 (Mob1a/1b), one of the important components in Hippo pathway, mutant mice were generated which has abnormal phenotype such as resistance to apoptosis and spontaneous tumorigenesis. Of note, Mats1/2 mutant mice also showed dental malocclusion. Therefore, in this study, we have evaluated the bone phenotype of Mats1/2 mutant mice. Although the mRNA expressions of Mats1 or Mats2 were observed in both osteoclastogenesis and osteoblastogenesis, the increase of Mats1 level was most prominent during osteoblastogenesis. The RANKL-induced osteoclast differentiation from bone marrow-derived macrophages (BMMs) was unaltered upon Mats1/2 mutation; however, the osteoblast differentiation using calvarial pre-osteoblasts was significantly reduced in Mats1/2 mutant mice compare to that of wild type mice. In accordance with in vitro results, Mats1/2 mutant mice showed decreased bone volume as well as increased trabecular separation in μCT analyses. These results may provide novel prospect of the probable linkage between Hippo pathway and bone homeostasis.

소나무재선충병의 나무주사는 살선충제를 중심으로 실시되어 왔으며, 매개충인 솔수염하늘소와 북방수염하늘소의 방제는 주로 항공방제나 지상방제를 통하여 이루어졌다. 본 연구에서는 나무주사를 통하여 매개충(솔수염하늘소)을 방제하기 위한 연구로 Abamectin+Acetamiprid ME, Thiamethoxam DC약제의 나무주사시 솔수염하늘소의 약효발현농도, 수목내 약제의 이동특성 및 치사율 등에 대해서 조사하였다. 실내 약효발현농도 시험에서는 Abamectin+Acetamiprid ME, Thiamethoxam DC 모두 0.1ppm 이상의 농도에서 평균 6일 경과 후 100.0% 치사하는 특성을 나타내었다. 또한 야산에서 나무주사를 통하여 솔수염하늘소에 대한 효과검토 결과, Abamectin+Acetamiprid ME, ThiamethoxamDC 모두 처리 60일 후 90.9%의 치사율(가지섭식 14일 후 기준)을 나타내었으며, 죽지 않는 개체는 가지의 약제침투특성차이에 의한 것으로 판단된다.